diff --git a/nimbus/common/hardforks.nim b/nimbus/common/hardforks.nim
index c81e560ead..38dddd82b2 100644
--- a/nimbus/common/hardforks.nim
+++ b/nimbus/common/hardforks.nim
@@ -50,10 +50,14 @@ type
     Shanghai
     Cancun
 
-const lastPurelyBlockNumberBasedFork* = GrayGlacier
-# MergeFork is special because of TTD.
-const firstTimeBasedFork* = Shanghai
+const
+  lastPurelyBlockNumberBasedFork* = GrayGlacier
+
+  # MergeFork is special because of TTD.
+  firstTimeBasedFork* = Shanghai
 
+  # Meta Fork
+  EOFFork* = Cancun
 
 type
   CliqueOptions* = object
diff --git a/tools/t8n/t8n_test.nim b/tools/t8n/t8n_test.nim
index 4a86f57018..f3ceb3d5e7 100644
--- a/tools/t8n/t8n_test.nim
+++ b/tools/t8n/t8n_test.nim
@@ -498,6 +498,7 @@ const
       expOut: "exp.json",
     ),
     TestSpec(
+<<<<<<< HEAD
       name  : "EVM tracer nil stack crash bug",
       base  : "testdata/00-519",
       input : t8nInput(
@@ -569,6 +570,15 @@ const
       output: T8nOutput(trace: true, result: true),
       expOut: "istanbul.txt",
     ),
+    TestSpec(
+      name: "Validate pre-allocated EOF code",
+      base: "testdata/01-501",
+      input: t8nInput(
+        "alloc.json", "txs.json", "env.json", "Cancun", "",
+      ),
+      output: T8nOutput(alloc: true, result: false),
+      expExitCode: 3,
+    ),
   ]
 
 proc main() =
diff --git a/tools/t8n/testdata/01-501/alloc.json b/tools/t8n/testdata/01-501/alloc.json
new file mode 100644
index 0000000000..43024b43d7
--- /dev/null
+++ b/tools/t8n/testdata/01-501/alloc.json
@@ -0,0 +1,14 @@
+{
+  "a94f5374fce5edbc8e2a8697c15331677e6ebf0b": {
+    "balance": "0x0",
+    "code": "0xef01",
+    "nonce": "0x1",
+    "storage": {}
+  },
+  "a94f5374fce5edbc8e2a8697c15331677e6ebf0c": {
+    "balance": "0x0",
+    "code": "0xef0001010008020002000700020300000000000002020100025959b0000250b101b1",
+    "nonce": "0x1",
+    "storage": {}
+  }
+}
diff --git a/tools/t8n/testdata/01-501/env.json b/tools/t8n/testdata/01-501/env.json
new file mode 100644
index 0000000000..05d8ffaaae
--- /dev/null
+++ b/tools/t8n/testdata/01-501/env.json
@@ -0,0 +1,12 @@
+{
+  "currentCoinbase": "0xc94f5374fce5edbc8e2a8697c15331677e6ebf0b",
+  "currentDifficulty": null,
+  "currentRandom": "0xdeadc0de",
+  "currentGasLimit": "0x750a163df65e8a",
+  "parentBaseFee": "0x500",
+  "parentGasUsed": "0x0",
+  "parentGasLimit": "0x750a163df65e8a",
+  "currentNumber": "1",
+  "currentTimestamp": "1000",
+  "withdrawals": []
+}
diff --git a/tools/t8n/testdata/01-501/txs.json b/tools/t8n/testdata/01-501/txs.json
new file mode 100644
index 0000000000..fe51488c70
--- /dev/null
+++ b/tools/t8n/testdata/01-501/txs.json
@@ -0,0 +1 @@
+[]
diff --git a/tools/t8n/transition.nim b/tools/t8n/transition.nim
index 2585a4bb25..d9172cd46a 100644
--- a/tools/t8n/transition.nim
+++ b/tools/t8n/transition.nim
@@ -11,13 +11,14 @@
 import
   std/[json, strutils, tables, os, streams],
   eth/[rlp, trie, eip1559],
-  stint, stew/results,
+  stint, stew/[results, byteutils],
   "."/[config, types, helpers],
   ../common/state_clearing,
   ../../nimbus/[vm_types, vm_state, transaction],
   ../../nimbus/common/common,
   ../../nimbus/db/accounts_cache,
-  ../../nimbus/utils/utils,
+  ../../nimbus/evm/validate,
+  ../../nimbus/utils/[utils, eof],
   ../../nimbus/core/pow/difficulty,
   ../../nimbus/core/dao,
   ../../nimbus/core/executor/[process_transaction, executor_helpers],
@@ -429,6 +430,20 @@ proc transitionAction*(ctx: var TransContext, conf: T8NConf) =
       else:
         raise newError(ErrorConfig, "EIP-1559 config but missing 'currentBaseFee' in env section")
 
+    if com.forkGTE(EOFFork):
+      for address, acc in ctx.alloc:
+        if not hasEOFByte(acc.code):
+          continue
+
+        var c: Container
+        var res = c.decode(acc.code)
+        if res.isOk:
+          res = c.validateCode()
+
+        if res.isErr:
+          raise newError(ErrorConfig, "code at $1 considered invalid: $2" %
+            [address.toHex, res.error.toString])
+
     if com.isShanghaiOrLater(ctx.env.currentTimestamp) and ctx.env.withdrawals.isNone:
       raise newError(ErrorConfig, "Shanghai config but missing 'withdrawals' in env section")